Chicks that can't stand and hold one leg out straght

[goods876]

We just brought home 11 chicks that all seemed healthy when we left the feed store. That was yesterday, by last night four of the chicks could not stand and all hold one leg out straight while laying down. I have these four separated. I don't know if the issue is physical or a disease. Any thoughts?

 

[lightchick]

Sorry! I don't know.....wish I could help!